Non-aqueous Electrode Insulating Layer for Battery Stability
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Solution Overview
Problem
In non-aqueous electrolyte secondary batteries, there is a risk of metal elution from the positive electrode active material during charging, leading to potential short circuits and deposition of metallic lithium on the negative electrode, due to uneven distribution of charge carriers which causes local potential increases at the edge of the positive electrode active material layer.
Innovation Solution
The battery design includes a positive electrode with an insulating layer containing an inorganic filler and a second positive electrode active material, positioned along one end of the positive electrode active material layer, and a negative electrode with a longer width than the positive electrode, where the total capacity of the second positive electrode active material in the insulating layer is defined to compensate for the capacity of the first positive electrode active material, reducing metal elution and deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the negative electrode is designed to be larger than the positive electrode to prevent charge carrier deposition, then charge carrier storage capacity is improved, but local potential increase at the positive electrode edge occurs causing metal elution
Solution Approach 1:
The patent applies local quality by creating a potential equalizing layer specifically at the edge portion of the positive electrode, rather than uniformly across the entire electrode. This localized intervention addresses the local potential increase problem at the edge while maintaining the overall electrode design for charge carrier storage. The layer contains inorganic filler particles with specific properties (average diameter 0.01-10 μm) that facilitate charge carrier supply precisely where needed.
Solution Approach 2:
The potential equalizing layer acts as an intermediary between the positive electrode active material layer and the electrolyte solution. It mediates charge carrier transport by providing an additional pathway for charge carriers to reach the edge portions of the positive electrode, thereby preventing local potential increase and subsequent metal elution without interfering with the overall battery operation.
2Stability of the object's composition
If charge carriers diffuse into the non-facing part of the negative electrode active material layer, then charge carrier distribution is improved, but potential locally increases at the edge of the positive electrode active material layer
Solution Approach 1:
The patent applies preliminary action by pre-establishing the potential equalizing layer at the edge portion of the positive electrode before charging begins. This layer is prepared in advance with specific inorganic filler content and structure, ready to immediately facilitate charge carrier supply to edge portions when charging starts, preventing potential increase before it occurs.
3Reliability
If an insulating layer is added along the edge of the positive electrode active material layer to prevent short circuiting, then electrical insulation is improved, but metal elution still occurs due to potential increase
Solution Approach 1:
The patent applies composite materials by creating a potential equalizing layer that combines inorganic filler particles (such as metal oxides, metal nitrides, or metal carbides) with a binder polymer. This composite structure provides both the electrical insulation needed to prevent short circuits and the charge carrier supply capability needed to prevent potential increase and metal elution. The inorganic filler particles serve dual functions of insulation and charge carrier mediation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces the elution of transition metals from the positive electrode active material and minimizes the deposition of metallic lithium on the negative electrode, enhancing the battery's stability and performance by maintaining a more even potential distribution.
Implementation Method 1
the insulating layer contains an inorganic filler and a second positive electrode active material... the total capacity of the second positive electrode active material in the insulating layer is defined to compensate for the capacity of the first positive electrode active material
Implementation Method 2
charge carriers (lithium ions, etc.) are released into an electrolytic solution from the positive electrode active material layer. In this case, in a negative electrode, charge carriers in the electrolytic solution enter the negative electrode active material layer and are stored
Data Source
AI summary
A non-aqueous electrolyte secondary battery including electrode body having structure in which positive electrode and negative electrode are laminated with separator and non-aqueous electrolyte. The positive electrode includes positive electrode current collector, positive electrode active material layer which is disposed on positive electrode current collector and contains first positive electrode active material, and insulating layer which is disposed along one end of positive electrode active material layer in predetermined width direction, and contains inorganic filler and second positive electrode active material. The negative electrode includes negative electrode current collector, and negative electrode active material layer which is disposed on negative electrode current collector and contains negative electrode active material, in which length in width direction is longer than length of positive electrode active material layer in width direction, and negative electrode active material layer faces positive electrode active material layer and at least part of insulating layer.